Conventionally, there has been known a linear motor including a field magneton and an armature arranged to be opposed to the field magneton. One of the field magneton and the armature being provided as a stator and the other being provided as a mover and the linear motor moving the mover relatively to the stator. Specifically, the field magneton has a configuration in which a plurality of different permanent magnets, magnetic poles of which on the armature side are alternately different, arrayed in a row. The armature has a configuration in which a coil is wound around a core. That is, the coil is subjected to energization control, whereby the linear motor relatively moves the armature and the mover linearly in an arraying direction of the permanent magnets.
For example, Japanese Patent Application Laid-open No. 2004-312983 discloses a linear motor including a track rail to which the field magneton (the permanent magnets) is fixed and a movable body movably supported by the track rail and mounted with the armature. The track rail is formed in a U-shape in cross section including a bottom wall and a pair of sidewalls projecting from both sides in the width direction of the bottom wall. The field magneton (the permanent magnets) is fixed to the bottom wall. The movable body includes a pair of sliders arranged in the longitudinal direction of the track rail and a connecting top plate that connects the sliders. The sliders are arranged between both the sidewalls of the track rail and are respectively movably supported by both the sidewalls. The armature is interposed between both the sliders to be opposed to the field magneton and is fixed to the combining top plate.
The linear motor is applied to various industrial machines and is also applied to a component mounting device that conveys an electronic component onto a board and mounts the electronic component on the board. For example, Japanese Patent Application Laid-open No. 2009-171681 describes a component mounting device that drives, using a linear motor, a nozzle for component attraction to ascend and descend. In the linear motor applied to the component mounting device, an armature and a linear guide (a guide device) are provided to be laterally arranged on the same surface of a frame member. A slide base is fixed to sliders of the linear guide. A field magneton (permanent magnets) is fixed on a side surface of the slide base. That is, the component mounting device moves the slide base (up and down) according to the driving by the linear motor to move the nozzle connected to the slide base up and down.
The linear motor disclosed in Japanese Patent Application Laid-open No. 2004-312983 includes a structure in which the armature is arranged between the pair of sliders. Therefore, in the linear motor, when the total length of the armature increases, a moment acting on both the sliders increases because of a load of the armature. As a result, it is likely that smooth movement of the movable body is hindered. In the linear motor, since the movable body is interposed between the pair of sidewalls of the track rail, an extra dimension is necessary in the width direction (a direction orthogonal to both of a direction in which the armature and the field magneton are opposed to each other and a moving direction of the movable body) by the thickness of the sidewalls. This is disadvantageous in making the entire linear motor compact in the width direction.
On the other hand, with the linear motor disclosed in Japanese Patent Application Laid-open No. 2009-171681, since the stator includes the armature as explained above, unlike the linear motor disclosed in Japanese Patent Application Laid-open No. 2004-312983, it is unlikely that smooth movement of the movable body (the slide base) is hindered by expansion of the entire length of the armature. Moreover, in the linear motor disclosed in Japanese Patent Application Laid-open No. 2009-171681, the armature and the linear guide are provided to be laterally arranged on the same surface of the frame member and then the slide base is fixed to the sliders of the linear guide and the field magneton (the permanent magnets) is fixed to the side surface of the slide base. Compared with the linear motor disclosed in Japanese Patent Application Laid-open No. 2004-312983, this is advantageous in making the entire linear motor compact in the width direction (a direction orthogonal to both of a direction in which the armature and the field magneton are opposed to each other and a moving direction of the slide base). However, in the linear motor disclosed in Japanese Patent Application Laid-open No. 2009-171681, since the armature and the linear guide are provided to be laterally arranged on the same surface of the frame member, an occupied space in the lateral arrangement direction is relatively large. It is difficult to make the entire linear motor compact in the lateral arrangement direction, that is, the direction in which the armature and the field magneton are opposed to each other. Therefore, improvement is demanded in this regard. Note that, in this case, if it is possible to reduce the number of components included in the linear motor, the reduction in the number of components is convenient from the viewpoint of a reduction in manufacturing costs and improvement of assemblability.